Geographic Range

Camponotus pennsylvanicus, the black carpenter ant, is native to the Nearctic region. Its range covers the eastern half of the United States, and it is the most common Camponotus species in the central and eastern United States. It also is present in eastern Canada. Specimens have been found in Bermuda, but it is unclear whether the species is established there. (Buczkowski, 2011; Sanders, 1972; Verble and Stephen, 2009; Wetterer and Wetterer, 2004)

Physical Description

As indicated by its common name, black carpenter ant, this species is black in color. It has one petiole (a node in the constriction between the thorax and abdomen). Like some other ant species, Camponotus pennsylvanicus is polymorphic. Several different sizes and forms exist in the colony, including small (minor) and large (major) workers. Camponotus pennsylvanicus is one of the largest species of carpenter ants; the large workers are about 0.5 to 1.6 cm long. The queen is about 1.9 cm long, on average. Workers are wingless, while males and sexual females have wings. Queens lose their wings once they establish a new colony. Camponotus pennsylvanicus can be distinguished from other ant species by the many distinctive hairs on its abdomen. (Fowler, 1984; Morgan, 1997; Ogg, 2013)

Development

Ants are holometabolous. Eggs hatch after about 18 to 25 days and then spend 14 to 25 days as larvae in the nest. Larvae are cared for and fed by adult workers. Larvae then spin cocoons and become pupae. After about 25 days, they emerge as adults. Eggs that hatch in the late summer overwinter as larvae, typically for about 6 months. Laboratory-maintained colonies that do not overwinter resume growth and mating in January, suggesting that true diapause ends in January. (Cannon and Fell, 1992; Gibson and Scott, 1990)

Reproduction

The mating ritual of Camponotus pennsylvanicus males and winged females mainly consists of a nuptial flight that usually takes place in the summer, often in July. Males produce a pheromone that impels females to take flight and find mates. A limited number of females participate in these annual swarms. After mating, each female ventures off to establish a new colony with her fertilized eggs. A new queen often finds a hole or knot within a tree and lays her eggs inside, tending to them until they hatch, metamorphose, and become her workers. These workers then care for subsequent batches of eggs and expand the nest. Males do not return to the colony and die shortly after mating. Sexual females and males may not be produced until several years after the parent colony has been established. (Forbes, 1956; Fowler and Roberts, 1982a; Loiacono and Margaria, 2003)

Camponotus pennsylvanicus has bimodal oviposition. Eggs laid in the spring produce workers, while eggs laid in August and September produce sexual forms. Eggs laid in the late summer hatch and overwinter as larvae, becoming workers in the following June and July. A queen that establishes a colony first lays a clutch of 5 to 15 eggs, which produce workers. Second-season and later queens lay larger batches of eggs. A queen stores the sperm from her first mating and continues to lay eggs throughout her lifetime. Fertilized eggs become female workers, while unfertilized eggs become males. Males are produced seasonally, and males have half the number of chromosomes as females. Most females are sterile workers; however, when conditions are favorable, sexually reproductive winged females are produced. (Cannon and Fell, 2002; Gibson and Scott, 1990; Loiacono and Margaria, 2003)

Camponotus pennsylvanicus likely provisions its eggs. Because the species has a eusocial system, when eggs hatch, the offspring remain in the nest as larvae and pupae and join the colony ranks once they reach adulthood. Workers provide protection and brood care for the larvae, bringing the larvae food from outside the nest and feeding larvae via trophallaxis, which involves the regurgitation of food stored in their crops. (Fowler, 1983)

Parental Investment

pre-hatching/birth

provisioning

female

protecting

female

pre-weaning/fledging

provisioning

female

protecting

female

pre-independence

provisioning

female

protecting

female

Lifespan/Longevity

Camponotus pennsylvanicus queens can live for over 10 years. Because males die shortly after mating, their lifespan likely is a few weeks to a few months. Sterile female workers can live for a few months to several years, even 7 years or more. (Loiacono and Margaria, 2003; Morgan, 1997)

Range lifespanStatus: wild

10+ (high) years

Typical lifespanStatus: wild

0.5 to 7+ years

Behavior

Camponotus pennsylvanicus lives in large colonies in nests built within trees, dead logs, or wooden building structures. The number of ants in one colony has not been documented for this species, but other ant species can have several thousand to 100,000 individuals in a single colony. As eusocial insects, C. pennsylvanicus individuals have defined roles within the colony. The queen lays eggs, and other workers tend to the queen. Smaller/minor workers typically tend aphids and collect aphid honeydew, while larger/major workers are more involved with maintaining the nest, expanding the nest by chewing wood, and defending colony resources. Middle- to large-sized workers also care for the larvae. Males have short lifespans and do little more than find a mate. Winged females find mates and establish new colonies. Black carpenter ants are mainly nocturnal and collect most of their food at night. They generally do not forage during the hottest parts of the day (mid-afternoon) and lay low during that time. Most foraging activity occurs right after sunset. The colony overwinters in its nest. Camponotus pennsylvanicus remains inactive throughout the winter, except for unseasonably warm days. These ants remain inactive when the ambient temperature is below 5 degrees Celsius. Nest construction within a log or tree trunk ensures that the interior temperature of the nest remains warm. Colonies reared in the laboratory do not overwinter when maintained at a constant temperature throughout the year. Lab colonies get slightly sluggish during the winter months, though they continue to forage. (Boroczky, et al., 2013; Buczkowski, 2011; Cannon and Fell, 1992; Cannon and Fell, 2002; Fowler, 1983; Helmy and Jander, 2003; Verble and Stephen, 2009)

Home Range

Most colonies of Camponotus pennsylvanicus have a parent nest, as well as several satellite nests. The documented range of one particular colony spanned an area between 6 and 28 square meters and occupied 1 to 6 trees in that area, which included the parent and satellite nests. (Buczkowski, 2011; Klotz, et al., 1998)

Vision and chemical detection are the most important senses for communication and perception in ants. To find food, a scout leaves the colony and searches until it finds a food source. It eats until satisfied, then uses pheromones to lay a chemical trail leading back to the nest for others to follow. The scout lays the trail by moving the tip of its abdomen along the surface of the substrate on which it travels. When it returns to the colony, the scout makes the food source known to others by a wiggling dance display, which involves vibrating its head and thorax back and forth. The scout may run quickly from group to group doing this dance, which maximizes the number of other ants that become aware of the food source. The scout also may offer food from the source to other ants in the colony. This offering often is followed by physical contact between the ants, such as knocking antennae and forelegs against one another. The ants then follow the chemical trail to find the food source. Because of the chemical trail, the scout often remains back at the nest and does not need to lead other ants to the food source. These chemical trails are particularly important because C. pennsylvanicus mostly forages at night. In the absence of moonlight or man-made light, C. pennsylvanicus relies on the chemical trails; however, the species has been shown to follow light sources when foraging at night. It also has been shown to use structural elements and tactile cues in its environment, such as tree roots or cracks in cement. An accessory gland in C. pennsylvanicus produces formic acid, which serves as an alarm signal to other ants and in low doses can increase the recruitment of ants to trails. Queens produce a pheromone that attracts workers and attendants to care for her. Males produce pheromones to initiate the nuptial flight in females. (Boroczky, et al., 2013; Fowler and Roberts, 1982b; Helmy and Jander, 2003; Hillery and Fell, 2000; Klotz and Reid, 1993; Traniello, 1977)

Food Habits

Camponotus pennsylvanicus is omnivorous. It is important to note that, although the species establishes nests in trees and decaying wood, C. pennsylvanicus does not actually feed on wood. It preys on many insect species, including aphids and occasionally lepidopteran larvae. It also farms aphids, eating the honeydew that the aphids produce. Camponotus pennsylvanicus is a noted predator of many forest pests and may have played a role in the significant population decline of the red oak borer, Enaphalodes rufulus. It also eats plant nectar, fruit, and some fungi. Camponotus pennsylvanicus often scavenges food or trash left behind by humans, eating almost anything, including honey, tuna fish, hot dogs, and cookies. Camponotus pennsylvanicus exhibits trophallaxis, which is when liquid nutrients are stored in the crop of the ant and later are regurgitated and shared with adults or larvae in the colony. Trophallaxis can facilitate the transfer of antimicrobials among colony members, which increases immunity to disease within the colony. Food and scavenging habits tend to change throughout the year as the needs of the colony change. More protein is collected in the early spring and summer to provision the developing larvae. Later in the summer, as the number of worker ants grows, carbohydrates (such as honeydew) become the primary source of energy. (Cannon and Fell, 2002; Hamilton, et al., 2011; Helmy and Jander, 2003; Inayat, et al., 2012; MacGown and Brown, 2006; Oberg, et al., 2012; Tripp, et al., 2000; Verble and Stephen, 2009; Youngsteadt and Devries, 2005)

Predation

Little information is available regarding predation on Camponotus pennsylvanicus. Insectivorous birds that inhabit the eastern half of the United States are predators; however, nocturnal foraging by C. pennsylvanicus helps to eliminate much of the bird predation that affects other carpenter ant species. When provoked, carpenter ants lunge forward with their mandibles held apart. Fights have been observed between colonies of other carpenter ant species, particularly Camponotus herculeanus, although such fights tend to result in the mutilation and death of many workers, rather than predation. (Carney, 1969; Klotz, et al., 1998; Sanders, 1964)

Ecosystem Roles

Camponotus pennsylvanicus likely serves as prey for several bird species. Individuals parasitized by the fluke Brachylecithum mosquensis are more conspicuous to predatory birds (which in turn serve as the definitive host of B. mosquensis) because the fluke causes its ant host to become sluggish, grow obese, and exhibit abnormal behavior. Camponotus pennsylvanicus serves as a host to several other parasites. The parasitoid phorid fly, Apocephalus concisus, attacks C. pennsylvanicus; emergence of the fly larva can cause decapitation of the ant host. Another phorid fly, Trucidophora camponoti, parasitizes alate (winged) females. The fungus Ophiocordyceps unilateralis kills C. pennsylvanicus and can be found growing from the head of an infected ant. Camponotus pennsylvanicus preys on many arthropod species, such as aphids, spiders, and many forest pest species. Some colonies farm aphids (including wooly alder aphids), eating the honeydew produced by the aphids and in turn protecting the aphids from predators. Blochmannia pennsylvanicus is a proteobacterium that functions as an obligate endosymbiont with C. pennsylvanicus, metabolizing nitrogen for its ant host. This proteobacterium is found in some midgut cells and in the ovaries of females. Because C. pennsylvanicus nests in decaying wood, it aids in biodegradation. (Brown, 2002; Brown, et al., 1991; Carney, 1969; Gosalbes, et al., 2010; Inayat, et al., 2012; Morgan, 1997; Oberg, et al., 2012; Van Pelt, 1958; Youngsteadt and Devries, 2005)

Economic Importance for Humans: Positive

Camponotus pennsylvanicus preys on many insect species that are pests to humans, including aphids and termites, which can decrease damage to crops and buildings. However, the ant species does not serve as a significant method of pest control. (Morgan, 1997; Morgan, 1997)

Positive Impacts

controls pest population

Economic Importance for Humans: Negative

Camponotus pennsylvanicus is considered to be the most significant structural pest in urban areas of the eastern United States. Because it colonizes trees and decaying wood, C. pennsylvanicus can invade the wooden structures of houses and other buildings as it tunnels during nest expansion, potentially causing severe structural damage. Wooden structures that are prone to moisture tend to be most at risk of infestation. Millions of dollars are estimated to be spent each year in attempts to eliminate C. pennsylvanicus nests and prevent damage. Much research has been conducted to determine the most effective insecticides and other means of controlling C. pennsylvanicus. (Buczkowski, 2011; Klotz, et al., 1996; Morgan, 1997; Ogg, 2013; Tripp, et al., 2000)

Contributors

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

agricultural

living in landscapes dominated by human agriculture.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

biodegradation

helps break down and decompose dead plants and/or animals

chemical

uses smells or other chemicals to communicate

colonial

used loosely to describe any group of organisms living together or in close proximity to each other - for example nesting shorebirds that live in large colonies. More specifically refers to a group of organisms in which members act as specialized subunits (a continuous, modular society) - as in clonal organisms.

diapause

a period of time when growth or development is suspended in insects and other invertebrates, it can usually only be ended the appropriate environmental stimulus.

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

eusocial

the condition in which individuals in a group display each of the following three traits: cooperative care of young; some individuals in the group give up reproduction and specialize in care of young; overlap of at least two generations of life stages capable of contributing to colony labor

fertilization

union of egg and spermatozoan

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

hibernation

the state that some animals enter during winter in which normal physiological processes are significantly reduced, thus lowering the animal's energy requirements. The act or condition of passing winter in a torpid or resting state, typically involving the abandonment of homoiothermy in mammals.

internal fertilization

fertilization takes place within the female's body

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

metamorphosis

A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

omnivore

an animal that mainly eats all kinds of things, including plants and animals

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

pheromones

chemicals released into air or water that are detected by and responded to by other animals of the same species

polymorphic

"many forms." A species is polymorphic if its individuals can be divided into two or more easily recognized groups, based on structure, color, or other similar characteristics. The term only applies when the distinct groups can be found in the same area; graded or clinal variation throughout the range of a species (e.g. a north-to-south decrease in size) is not polymorphism. Polymorphic characteristics may be inherited because the differences have a genetic basis, or they may be the result of environmental influences. We do not consider sexual differences (i.e. sexual dimorphism), seasonal changes (e.g. change in fur color), or age-related changes to be polymorphic.
Polymorphism in a local population can be an adaptation to prevent density-dependent predation, where predators preferentially prey on the most common morph.

riparian

Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

scent marks

communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

sperm-storing

mature spermatozoa are stored by females following copulation. Male sperm storage also occurs, as sperm are retained in the male epididymes (in mammals) for a period that can, in some cases, extend over several weeks or more, but here we use the term to refer only to sperm storage by females.

suburban

living in residential areas on the outskirts of large cities or towns.

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

urban

living in cities and large towns, landscapes dominated by human structures and activity.

visual

uses sight to communicate

References

Boroczky, K., A. Wada-Katsumataa, D. Batchelor, M. Zhukovskaya, C. Schal. 2013. Insects groom their antennae to enhance olfactory acuity. Proceedings of the National Academy of Sciences of the United States of America, 110/9: 3615-3620.

Fowler, H., R. Roberts. 1982. Seasonal Occurrence of Founding Queens and the Sex Ratio of Camponotus pennsylvanicus (Hymenoptera: Formicidae) in New Jersey. Journal of the New York Entomological Society, 90/4: 247-251.

Youngsteadt, E., P. Devries. 2005. The effects of ants on the entomophagous butterfly caterpillar Feniseca tarquinius, and the putative role of chemical camouflage in the Feniseca-Ant interaction. Journal of Chemical Ecology, 31/9: 2091-2109.

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The Animal Diversity Web is an educational resource written largely by and for college students. ADW doesn't cover all species in the world, nor does it include all the latest scientific information about organisms we describe. Though we edit our accounts for accuracy, we cannot guarantee all information in those accounts. While ADW staff and contributors provide references to books and websites that we believe are reputable, we cannot necessarily endorse the contents of references beyond our control.

This material is based upon work supported by the
National Science Foundation
Grants DRL 0089283, DRL 0628151, DUE 0633095, DRL 0918590, and DUE 1122742. Additional support has come from the Marisla Foundation, UM College of Literature, Science, and the Arts, Museum of Zoology, and Information and Technology Services.